ASTM E3127-24
(Guide)Standard Guide for Specifying Water Vapor Transmission Material Properties of Water-Resistive Barriers and Air Barriers
Standard Guide for Specifying Water Vapor Transmission Material Properties of Water-Resistive Barriers and Air Barriers
SIGNIFICANCE AND USE
4.1 As the building industry shifts towards performance-based design, specification of material properties consistent with anticipated in-service conditions becomes paramount to the design process. When specifying water vapor transmission properties, it is important to identify water vapor transmission properties for WRB/AB products that are measured under test conditions relevant to anticipated in-service conditions. This guide provides a performance-based framework for characterizing the water vapor transmission properties of WRB/AB.
4.2 When specifying WRB/AB, water vapor permeance is an important attribute to consider for proper moisture management and functioning of wall and roof assemblies in service. In North America, water vapor transmission properties of water-resistive and air barrier materials are traditionally tested in accordance with Test Methods E96/E96M. This guide adopts the ASTM E96/E96M test methods as a primary source of information for water vapor transmission properties of WRB/AB unless otherwise instructed by the design professional.
4.3 Most standard test methods rely on a limited set of steady-state testing conditions for evaluating the water vapor transmission properties of materials. Test conditions used to measure and report water vapor transmission values of WRB/AB should represent the in-service conditions of the tested material as closely as possible (that is, should cover the range of temperature and relative humidity conditions the products will experience when installed in wall and roof assemblies). The water vapor permeance of many WRB/AB materials can vary by more than an order of magnitude when tested for ranges of temperatures and relative humidity expected in service. For this reason, WVT properties over the full range of environmental conditions that the material will most likely experience in service should be used or evaluated when specifying a material or assembly design for a specific project.
SCOPE
1.1 This document covers guidelines for specifying water vapor transmission (WVT) properties for above-grade water-resistive barriers and air barriers (WRB/AB), typically installed between building structural components and cladding that compose the exterior side of building envelopes in North America.
1.2 This guide applies to all types of water-resistive barrier and air barrier products, including multifunctional products, regardless of the manufacturing process, type of material, or installation technique.
1.3 This guide provides general provisions for specifying and reporting the water vapor transmission properties of WRB/AB determined by standardized test methods, in accordance with in-service conditions these products typically experience within building envelopes.
1.4 It is beyond the scope of this guide to optimize the water vapor transmission characteristics of WRB/AB for specific conditions of use. The specific conditions of use should account for variations in indoor and outdoor climates, cladding type, moisture storage capacity of cladding materials, thermal insulating measures for wall and roof assemblies, air movement, and vapor diffusion control strategies.
1.5 This guide does not address proper installation and integration of WRB/AB with other wall and roof components.
1.6 The values stated in inch-pound units are to be regarded separately as standard. Within the text, the SI units shown in parentheses are provided for information only. The values stated in each system are not exact equivalents; therefore, each system shall be used independently. Combining values from two systems may result in non-conformance with the standard. However, derived results can be converted between systems using appropriate conversion factors (see Table 1).
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish approp...
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E3127 − 24
Standard Guide for
Specifying Water Vapor Transmission Material Properties of
1
Water-Resistive Barriers and Air Barriers
This standard is issued under the fixed designation E3127; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This document covers guidelines for specifying water
responsibility of the user of this standard to establish appro-
vapor transmission (WVT) properties for above-grade water-
priate safety, health, and environmental practices and deter-
resistive barriers and air barriers (WRB/AB), typically in-
mine the applicability of regulatory limitations prior to use.
stalled between building structural components and cladding
1.8 This international standard was developed in accor-
that compose the exterior side of building envelopes in North
dance with internationally recognized principles on standard-
America.
ization established in the Decision on Principles for the
1.2 This guide applies to all types of water-resistive barrier
Development of International Standards, Guides and Recom-
and air barrier products, including multifunctional products,
mendations issued by the World Trade Organization Technical
regardless of the manufacturing process, type of material, or
Barriers to Trade (TBT) Committee.
installation technique.
2. Referenced Documents
1.3 This guide provides general provisions for specifying
2
2.1 ASTM Standards:
and reporting the water vapor transmission properties of
C168 Terminology Relating to Thermal Insulation
WRB/AB determined by standardized test methods, in accor-
C578 Specification for Rigid, Cellular Polystyrene Thermal
dance with in-service conditions these products typically
Insulation
experience within building envelopes.
C1289 Specification for Faced Rigid Cellular Polyisocyanu-
1.4 It is beyond the scope of this guide to optimize the water
rate Thermal Insulation Board
vapor transmission characteristics of WRB/AB for specific
D226/D226M Specification for Asphalt-Saturated Organic
conditions of use. The specific conditions of use should
Felt Used in Roofing and Waterproofing
account for variations in indoor and outdoor climates, cladding
D779 Test Method for Determining the Water Vapor Resis-
type, moisture storage capacity of cladding materials, thermal
tance of Sheet Materials in Contact with Liquid Water by
insulating measures for wall and roof assemblies, air
the Dry Indicator Method
movement, and vapor diffusion control strategies.
D1079 Terminology Relating to Roofing and Waterproofing
D1653 Test Methods for Water Vapor Transmission of Or-
1.5 This guide does not address proper installation and
ganic Coating Films
integration of WRB/AB with other wall and roof components.
D3833/D3833M Test Method for Water Vapor Transmission
1.6 The values stated in inch-pound units are to be regarded
of Pressure-Sensitive Tapes
separately as standard. Within the text, the SI units shown in
E96/E96M Test Methods for Gravimetric Determination of
parentheses are provided for information only. The values
Water Vapor Transmission Rate of Materials
stated in each system are not exact equivalents; therefore, each
E398 Test Method for Water Vapor Transmission Rate of
system shall be used independently. Combining values from
Sheet Materials Using Dynamic Relative Humidity Mea-
two systems may result in non-conformance with the standard.
surement
However, derived results can be converted between systems
E631 Terminology of Building Constructions
using appropriate conversion factors (see Table 1).
E2556/E2556M Specification for Vapor Permeable Flexible
Sheet Water-Resistive Barriers Intended for Mechanical
Attachment
1
This guide is under the jurisdiction of ASTM Committee E06 on Performance
of Buildings and is the direct responsibility of Subcommittee E06.41 on Air
2
Leakage and Ventilation Performance. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2024. Published March 2024. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2022. Last previous edition approved in 2022 as E3127 – 22. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E3127-24. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E3127 − 22 E3127 − 24
Standard Guide for
Specifying Water Vapor Transmission Material Properties of
1
Water-Resistive Barriers and Air Barriers
This standard is issued under the fixed designation E3127; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This document providescovers guidelines for specifying water vapor transmission (WVT) properties for above-grade
water-resistive barriers and air barriers (WRB/AB), typically installed between building structural components and cladding that
compose the exterior side of building envelopes in North America.
1.2 This guide applies to all types of water-resistive barrier and air barrier products, including multifunctional products, regardless
of the manufacturing process, type of material, or installation technique.
1.3 This guide provides general provisions for specifying and reporting the water vapor transmission properties of WRB/AB
determined by standardized test methods, in accordance with in-service conditions these products typically experience within
building envelopes.
1.4 It is beyond the scope of this guide to optimize the water vapor transmission characteristics of WRB/AB for specific conditions
of use. The specific conditions of use should account for variations in indoor and outdoor climates, cladding type, moisture storage
capacity of cladding materials, thermal insulating measures for wall and roof assemblies, air movement, and vapor diffusion control
strategies.
1.5 This guide does not address proper installation and integration of WRB/AB with other wall and roof components.
1.6 The values stated in inch-pound units are to be regarded separately as standard. Within the text, the SI units shown in
parentheses are provided for information only. The values stated in each system are not exact equivalents; therefore, each system
shall be used independently. Combining values from two systems may result in non-conformance with the standard. However,
derived results can be converted between systems using appropriate conversion factors (see Table 1).
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
1
This guide is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.41 on Air Leakage and
Ventilation Performance.
Current edition approved May 1, 2022March 1, 2024. Published July 2022March 2024. Originally approved in 2022. Last previous edition approved in 2022 as E3127 – 22.
DOI: 10.1520/E3127-22.10.1520/E3127-24.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E3127 − 24
A, B
TABLE 1 Units and Conversion Factors
To Obtain (for the
Multiply By
same test condition)
C
WVT
2 2
g/h·m 1.43 grains/h·ft
2 2
grains/h·ft 0.697 g/h·m
Permeance
2 7
g/Pa·s·m 1.75 × 10 1 Perm (Inch-pound)
D -8 2
1 Perm (Inch-pound) 5.72 × 10 g/Pa·s·m
Permeability
8
g/Pa·s·m 6.88 × 10 1 Perm-inch
-9
1 Perm-inch 1.45 × 10 g/Pa·s·m
A
These units are used in the construction trade. Other units may be used in other
standards.
B
All conversions of mm Hg to Pa are made at a temperature of 0 °C.
C
WVT = water vapor transmission.
D 2
1 Perm = 1 US Perm = 1 grains/h·ft ·in. Hg.
2. Referenced Documents
2
2.1 ASTM Standards:
C168 Terminology Relating to Thermal Insulation
C578 Specification for Rigid, Cellular Polystyrene Thermal Insulation
C1289 Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board
D226/D226M Specification for Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing
D779 Test Method for Determining the Water Vapor Resistance of Sheet Materials in Contact with Liquid Water by the Dry
...
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